Flatten non-static NullRestricted fields #18173
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runtime/oti/j9.h
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| @@ -337,6 +337,7 @@ static const struct { \ | |||
| * Disable flattening of volatile field that is > 8 bytes for now, as the current implementation of copyObjectFields() will tear this field. | |||
| */ | |||
| #define J9_IS_FIELD_FLATTENED(fieldClazz, romFieldShape) \ | |||
| J9_ARE_NO_BITS_SET((romFieldShape)->modifiers, J9FieldFlagIsNullRestricted) || \ | |||
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Only null restricted field can be potentially flattened with the newer javac, so it should be sth like J9_ARE_ALL_BITS_SET((romFieldShape)->modifiers, J9FieldFlagIsNullRestricted) && (ALL the existing conditions of J9_IS_FIELD_FLATTENED)
As the current javac does not produce null restricted attribute yet, for now to keep the builds working, we can keep this macro unchanged and add a new macro J9_IS_NULL_RESTRICTED_FIELD_FLATTENED and define it to
J9_ARE_ALL_BITS_SET((romFieldShape)->modifiers, J9FieldFlagIsNullRestricted) && J9_IS_FIELD_FLATTENED().
Then in this line, you can use J9_IS_NULL_RESTRICTED_FIELD_FLATTENED. Eventually we will remove the current J9_IS_FIELD_FLATTENED and rename J9_IS_NULL_RESTRICTED_FIELD_FLATTENED to J9_IS_FIELD_FLATTENED.
Also this line should be removed as it will always be false with the new javac. (If there are tests failed due to this remval, the test should be either rewritten or disabled)
But I think these changes can be done under #18157, not necessarily in this PR.
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runtime/oti/j9.h
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| @@ -339,6 +339,10 @@ static const struct { \ | |||
| #define J9_IS_FIELD_FLATTENED(fieldClazz, romFieldShape) \ | |||
| (J9_IS_J9CLASS_FLATTENED(fieldClazz) && \ | |||
| (J9_ARE_NO_BITS_SET((romFieldShape)->modifiers, J9AccVolatile) || (J9CLASS_UNPADDED_INSTANCE_SIZE(fieldClazz) <= sizeof(U_64)))) | |||
| /* This will replace J9_IS_FIELD_FLATTENED when QTypes are removed */ | |||
| #define J9_IS_NULL_RESTRICTED_FIELD_FLATTENED(fieldClazz, romFieldShape) \ | |||
| J9_ARE_ALL_BITS_SET((romFieldShape)->modifiers, J9FieldFlagIsNullRestricted) && \ | |||
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I see J9_IS_J9CLASS_FLATTENED(fieldClazz) is removed. After looking at the code closer, I think we should still keep J9_IS_J9CLASS_FLATTENED(fieldClazz), as user can use -XX:ValueTypeFlatteningThreshold=<size> to control whether J9ClassIsFlattened will be set on a J9Class based on the instance size. This should change the field flattening behaviour.
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yes thats true. that addition will make it so J9_IS_NULL_RESTRICTED_FIELD_FLATTENED since its only true for primitive value classes but its going to get messier before it gets better.
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I have added J9_IS_NULL_RESTRICTED_FIELD_FLATTENED
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Signed-off-by: Theresa Mammarella <Theresa.T.Mammarella@ibm.com>
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Jenkins test sanity,extended zlinuxval jdknext |
Related: #17340